It is proposed to elucidate the pathway of biosynthesis of 1-acetoxy-6-amino-octahydroindolizine (V) and 3,4,5-trihydroxyoctahydroindolizine (XXI) in Rhizoctonia leguminicola. Pipecolic acid (II) is a precursor of V and XXI; it is hypothesized that malonate condenses with II giving VI which serves alternatively to condense in such a manner as to give either indolizine or pyrindine precursors of V and XXI respectively. Evidence for the formation of these ring systems from VI followed by subsequent metabolic events leading to V and XXI will be studied. The experimental approach will employ the use of 13C and deuterium labeled precursors, followed by subsequent nmr and mass spectroscopic techniques to characterize biosynthesized products. Enzymatic evidence for postulated metabolic transformations in cell free fungal extracts will be sought.